1. Field of the Invention
The present invention relates to a device for sealing the pulp cavity and root canals of a devitalized tooth.
2. Description of Related Art
The volume formed by the root system of the tooth is blind because air cannot escape via the apical end of each root. The air therefore escapes as it were via the access formed by the dentist during traditional sealing. Dead volumes may not be filled, presenting both a risk of infection and a weakening of the structure of the tooth.
Filling under vacuum is thus very well suited to sealing the root canals of the teeth after these have been devitalized. The fluid conveyed under vacuum reaches the farthest recesses of the canal geometry, including the entrance of the radial canaliculi on the surface of the walls of each root. The effect of this is to reinforce the structure of the tooth, giving it increased strength.
It has already been proposed to seal devitalized teeth by first applying a high vacuum to the pulp cavity and then connecting this cavity to a source of fluid sealing product, which flows toward this cavity and fills it to the level of the canaliculi by means of the suction created by the vacuum. The first trials carried out by G. Korkhaus and R. Alfter in this field date back to 1958. However, their use was poorly suited to dental techniques and they did not go beyond the experimental stage.
EP 0,299,919 has proposed a method of devitalizing teeth using the phenomenon of cavitation, in which a hypochlorite solution is caused to form bubbles. Once the cleaning and disinfecting have been carried out, the pulp chamber is connected to the vacuum source used to create the cavitation, in order to remove all the liquid by vaporizing it at low pressure. Once the chamber has been dried, a vacuum is established therein and it is then connected to a source of fluid sealing product.
One of the problems associated with this solution lies in the large number of maneuvers needed to move on from the drying stage to the filling stage. Moreover, during the filling stage under vacuum, it is necessary to coordinate the activation of the piston of a syringe, intended to supply the sealing product, with this sealing product being brought into communication with the vacuum pump, which represents a very delicate phase left to the judgment of the operator. If the two actions are not simultaneous, that is to say if the action of the piston is delayed in relation to the sealing product being brought into communication with the underpressure in the cavity to be filled, the flow of the product is slowed down and there is a risk of poor filling of the cavity and especially of the canaliculi.
A proposal for remedying this disadvantage has been set out in U.S. Pat. No. 5,295,828, in which the sealing product is arranged in a reservoir which has an outlet opening for bringing this reservoir into communication with the pulp cavity to be filled, said outlet opening being closed off by a mechanical shutoff element, controlled manually by a lever which allows this shutoff element to be moved away from the outlet opening. The operator opens this shutoff element when the pulp cavity has been placed under vacuum. In this solution, a free piston is mounted in the reservoir in order to equalize the pressure exerted on the fluid sealing product. However, no pressure other than atmospheric pressure is exerted on this piston, so that the cavity is filled only by the suction caused by the underpressure. The communication between the vacuum pump and the pulp cavity is rapidly cut by the sealing product and the underpressure of the pulp cavity is not always sufficient to compensate the losses of head in the supply conduits.
The present invention relates to a device for sealing the pulp cavity and root canals of a devitalized tooth, comprising a vacuum pump, a first connecting conduit between this vacuum pump and said pulp cavity, a source of fluid substance for sealing this pulp cavity, a second connecting conduit between said source of fluid substance and said pulp cavity, and means for closing said second conduit in order to bring said source of fluid sealing substance selectively into communication with said cavity.
It is an object of the present invention to make it possible to exert simultaneously an underpressure downstream of the reservoir of fluid sealing product and an overpressure upstream thereof, guaranteeing perfect simultaneity of these two effects, in order to promote the filling of the cavity of the lateral canals and the canaliculi by the sealing product.
To this end, the subject of the present invention is a device for sealing the pulp cavity and the root canals of a devitalized tooth.
The overpressure exerted upstream has the main aim of compensating the losses of head in the conduits connecting the reservoir of sealing product and the devitalized pulp cavity. The presence of the calibrated membrane makes it possible to guarantee that the two forces, namely suction downstream and release of the spring upstream, are exerted simultaneously on the sealing product.